I have a mossberg 500 20ga that has decided not to fire everytime. This only started a couple weeks ago when I was shooting skeet with some buddies. I shot 3 boxes before it started to act up.

It doesn't matter if I load a shell by hand or pump the action to load a second shell. There is no guarantee whether or not it will fire.

If it doesn't fire you hear a faint click and there is no mark on the primer.

Can anyone suggest what may be the problem? I have cleaned it, oiled it, soaked the action with gun scrubber and then reoiled it again. Still no difference.

Thanks,